Superplastic Sinter-forging of Fine-grained Si{sub}3N{sub}4-Si{sub}2N{sub}2O Composite at Low Temperature

摘要

The Si{sub}3N{sub}4-Si{sub}2N{sub}2O composites are fabricated with amorphous nano-sized silicon nitride powders by the liquid phase sintering (LPS) method. XRD analysis shows sintered body consists of β-Si{sub}3N{sub}4 and Si{sub}2N{sub}2O. SEM experiment conforms that the average grain size of sintered body is less than 300nm. The complex-shape gears can be formed by a sinter-forging technology when the sintering temperature is 1600°C and the superplastic forging temperature is only 1550°C. Rod-shaped grains aligned along the perpendicular direction of pressure and the mechanical properties increase about 10% after the materials were forged.